Paper coating and drying machine

Abstract

A paper tinting and drying machine has a tinting module and a dryer module spaced apart from one another by a predetermined distance so that aqueous liquid ink with less than five percent volatile organic compounds by volume applied to the underside of the paper can be visually inspected by the machine operator and so that ink application adjustments located on the paper output side of the tinter module can be accessed by the machine operator. Rollers in the tinting module constrain the paper to follow a path of travel through two sets of inking rollers so that both sides of the paper are evenly coated. After entering the dryer module without smearing or transferring wet ink to the dryer module input guide roller, the ink on the paper is dried by air knives and infrared heaters within the dryer module. In a first embodiment, the rollers in the tinting module drive the paper through the machine. The speed of the drive rollers is determined by a machine operator control adjustment, and slack is eliminated by a slack-detecting device associated with a take-up device. In a second embodiment, the speed of rotation of the take-up device is monitored by a tachometer and the tachometer controls the speed of travel of the paper through the tinter module. In both embodiments, the paper is coated and dried in the substantial absence of stretching or curling.

What is claimed is: 
     
       1. A paper coating and drying machine, comprising: a tinting module;   a dryer module;   said tinting and dryer modules being longitudinally spaced apart from one another by a predetermined distance sufficient for a machine operator to visually inspect an underside of a web of wet paper exiting said tinting module;   a plurality of rollers disposed in said tinting module for applying ink to both sides of said web of paper, a first set of rollers for applying ink to a first side of said web of paper and a second set of rollers for applying ink to a second side of said web of paper;   motor means for driving said plurality of rollers disposed in said tinting module at a predetermined speed;   a plurality of idler rollers associated with said dryer module for constraining said web of paper to follow a predetermined path of travel through said dryer module;   a take-up means longitudinally spaced apart from said dryer module for coiling said web of paper as it exits said dryer module:   motor means for operating said take-up means at a speed of operation substantially equal to said predetermined speed of said plurality of rollers disposed in said tinting module;   a slack-detecting means associated with said take-up means, said slack-detecting means for increasing said speed of operation of said take-up means upon detection of a slack in said web of paper between said dryer module and said take-up means;   said motor means for driving said plurality of rollers disposed in said tinting module and said motor means for operating said take-up means and said slack-detecting means and said idler rollers associated with said dryer module collectively forming an anti-tensioning means for causing said web of paper to pass through said machine at substantially zero tension so that said web of paper is substantially undistorted.   
     
     
       2. The machine of claim 1, wherein said anti-tensioning means includes a tachometer mounted on said take-up means for monitoring the rotational speed of said take-up means and for generating a signal that controls the speed of rotation of said rollers in said tinting module so that said tinting module rollers rotate at a speed that feeds said web of paper through said tinting module at a speed substantially equal to the rotational speed of said take-up means. 
     
     
       3. The machine of claim 1, further comprising: a first ink trough disposed in said tinting module for holding a coating to be applied to a first side of a web of paper; and   a second ink trough disposed in said tinting module for holding a coating to be applied to a second side of a web of paper.   
     
     
       4. The machine of claim 3, further comprising a first fountain roller and a first metering roller disposed in rolling engagement therewith, said first fountain roller being rotatably mounted in cooperation with said first trough so that rotation of said first fountain roller at a predetermined slower surface speed than said first metering roller draws a constant flow of ink into a gap between said first fountain roller and said first metering roller. 
     
     
       5. The machine of claim 4, further comprising a second fountain roller and a second metering roller disposed in rolling engagement therewith, said second fountain roller being rotatably mounted in cooperation with said second trough so that rotation of said second fountain roller at a predetermined slower surface speed than said second metering roller draws a constant flow of ink into a gap between said second fountain roller and said second metering roller. 
     
     
       6. The machine of claim 5, further comprising a first applicator roller in rolling engagement with said first metering roller and a first impression roller in rolling engagement with said first applicator roller, said web of paper having a predetermined path of travel that carries it between said first applicator roller and said first impression roller. 
     
     
       7. The machine of claim 6, further comprising a second applicator roller in rolling engagement with said second metering roller and a second impression roller in rolling engagement with said second applicator roller, said web of paper having a predetermined path of travel that carries it between said second applicator roller and said second impression roller after said web of paper has passed between said first applicator roller and said first impression roller. 
     
     
       8. The machine of claim 7, further comprising an adjustment knob associated with said first fountain roller to control the amount of frictional engagement between said first fountain roller and said first metering roller. 
     
     
       9. The machine of claim 7, further comprising an adjustment knob associated with said second fountain roller to control the spacing between said second fountain roller and said second metering roller. 
     
     
       10. The machine of claim 7, further comprising an adjustment knob associated with said first impression roller to control the spacing between said first impression roller and said first applicator roller. 
     
     
       11. The machine of claim 7, further comprising an adjustment knob associated with said second impression roller to control the spacing between said second impression roller and said second applicator roller. 
     
     
       12. The machine of claim 7, wherein outer surfaces of said first and second metering rollers include a predetermined pattern of cells engraved thereon to control the volume of ink conveyed to said first and second applicator rollers, respectively. 
     
     
       13. The machine of claim 12, wherein said predetermined pattern of cells includes a cell size and a cell density, and wherein said cell size and cell density are preselected for suitability with chemical properties of the ink or coating in use. 
     
     
       14. The machine of claim 7, further comprising a first pneumatic cylinder means associated with said first applicator roller for displacing said first applicator roller out of rolling engagement with said first metering roller and said first impression roller when said machine is not in operation. 
     
     
       15. The machine of claim 14, further comprising a second pneumatic cylinder means associated with said second applicator roller for displacing said second applicator roller out of rolling engagement with said second metering roller and said second impression roller when said machine is not in operation. 
     
     
       16. The machine of claim 15, further comprising a tachometer mounted on said take-up means for monitoring a surface speed of said paper and for generating a signal that causes said first and second pneumatic cylinders to engage said first and second applicator rollers to their associated metering and impression rollers when said surface speed attains a predetermined value. 
     
     
       17. The machine of claim 15, further comprising a continuous belt disposed in interconnecting relation between said first and second metering rollers and a motor means for rotating said continuous belt so that said first and second metering rollers and hence said first and second fountain, applicator, and impression rollers rotate at coordinated speeds. 
     
     
       18. The machine of claim 17, further comprising means for monitoring the speed of said motor means and for generating a signal that causes said first and second pneumatic cylinders to engage said first and second applicator rollers to their associated metering and impression rollers when the speed of said motor means attains a predetermined value, said means for monitoring being a control tachometer connected to a preselected roller in said tinting module. 
     
     
       19. The machine of claim 3, further comprising a plurality of ink-holding tanks in fluid communication with said tinting module, there being a valve and a pump associated with each of said ink-holding tanks so that ink of differing colors is selectively deliverable to said first and second ink troughs. 
     
     
       20. The machine of claim 19, further comprising a first manifold fluidly connected to said tinting module for delivering ink from a preselected ink tank to said second ink trough. 
     
     
       21. The machine of claim 20, further comprising an overflow tube associated with said second ink trough so that when ink in said second ink trough reaches a predetermined level, it flows into said overflow tube so that ink in said second ink trough cannot exceed a predetermined level, said predetermined level being determined by the positioning of said overflow tube. 
     
     
       22. The machine of claim 21, wherein said first ink trough is positioned at a lower elevation than said second ink trough, and wherein said overflow tube is in fluid communication with said first ink trough so that ink flowing through said overflow tube enters into said first ink trough; whereby said first ink trough may be maintained in an empty condition by controlling the level of ink in said second ink trough to a level below that of the overflow tube.   
     
     
       23. The machine of claim 22, further comprising a second manifold fluidly connected to said tinting module for returning ink in said first ink trough to a preselected ink tank. 
     
     
       24. The machine of claim 1, wherein said dryer module houses at least one air knife and wherein the rollers in said dryer module are disposed to constrain said web of paper to pass near said at least one air knife so that vapor near a surface of said web of paper is stripped away by said at least one air knife. 
     
     
       25. The machine of claim 1, wherein said dryer module houses a pair of air knives disposed on opposite sides of a predetermined path of travel of said web of paper as it passes through said dryer module. 
     
     
       26. The machine of claim 25, wherein said dryer module houses at least one infrared heating means and wherein the rollers in said dryer module are disposed to constrain said web of paper to pass near said at least one infrared heating means as said web of paper travels through said dryer module. 
     
     
       27. The machine of claim 25, wherein said dryer module houses a pair of infrared heating means disposed on opposite sides of a predetermined path of travel of said web of paper as it travels through said dryer module, each of said infrared heating means being contained within a housing configured to direct forced air at said web as it passes said infrared heating means. 
     
     
       28. The machine of claim 27, further comprising an infeed roller disposed at a top end of said dryer module, a second roller disposed at a bottom end of said dryer module, a third roller disposed at a top end of said dryer module, a fourth roller disposed at a bottom end of said dryer module, and an outfeed roller disposed at a top end of said dryer module, said web of paper passing sequentially over said infeed roller, under said second roller, over said third roller, under said fourth roller, and over said outfeed roller as it travels through said dryer module. 
     
     
       29. The machine of claim 27, wherein said infeed roller and said second roller are positioned within said dryer module to constrain a first side of said web of paper to pass by a first air knife of said pair of air knives in a downward path of travel between said infeed roller and said second roller. 
     
     
       30. The machine of claim 29, wherein said second and third rollers are positioned within said dryer module to constrain a second side of said web of paper to pass by a second air knife of said pair of air knives in an upward path of travel between said second and third rollers. 
     
     
       31. The machine of claim 30, wherein said second and third rollers are positioned within said dryer module to constrain said second side of said web of paper to pass by a first infrared heater of said pair of infrared heaters and to constrain said web of paper to travel an upward path of travel between said second and third rollers. 
     
     
       32. The machine of claim 31, wherein said third and fourth rollers are positioned within said dryer module to constrain said web of paper to pass between said pair of infrared heaters and to constrain said web of paper to travel downwardly between said third and fourth rollers. 
     
     
       33. The machine of claim 32, wherein said fourth roller and said outfeed roller are positioned within said dryer module to constrain said first side of said web of paper to pass by a second infrared heater of said pair of infrared heaters and to constrain said web of paper to travel upwardly from said fourth roller to said outfeed roller. 
     
     
       34. The machine of claim 33, further comprising a partition wall disposed within said dryer module, said pair of air knives and said pair of infrared heaters being disposed above said partition wall and said second and fourth rollers being disposed below said partition wall so that said second and fourth rollers are substantially protected from the heat generated by said air knives and said infrared heaters. 
     
     
       35. The machine of claim 34, further comprising a plurality of slots formed in said partition wall to allow downward and upward travel of said web of paper as it travels between said rollers of said dryer module. 
     
     
       36. The machine of claim 35, further comprising a blower fan of predetermined capacity for blowing ambient air into said dryer module, said blower fan being mounted below said dryer module and said dryer module having an open bottom for admitting air impelled by said blower fan into said dryer module. 
     
     
       37. The machine of claim 36, further comprising a suction fan of predetermined capacity for drawing air from said dryer module, said suction fan being mounted below said dryer module. 
     
     
       38. The machine of claim 37, wherein said predetermined capacity of said suction fan is greater than that of said blower fan so that the air pressure in the interior of said dryer module is less than atmospheric pressure, whereby moisture-laden air is quickly removed from an interior of said dryer module and replaced by dry air from the ambient environment external to the dryer module. 
     
     
       39. The machine of claim 38, wherein said dryer module includes a frame made of hollow tubular members. 
     
     
       40. The machine of claim 39, further comprising a blower fan means mounted below said dryer module for blowing air into a hollow interior of said hollow tubular members. 
     
     
       41. The machine of claim 40, further comprising a plurality of first and second openings formed in said hollow tubular members at preselected locations. 
     
     
       42. The machine of claim 41, wherein said first plurality of openings is disposed adjacent said infeed roller of said dryer module so that air exiting said first plurality of openings impinges upon said web of paper just prior to its engagement with said infeed roller to aid in drying ink on said paper so that said ink is not smeared by passing over said infeed roller. 
     
     
       43. The machine of claim 42, wherein said second plurality of openings is disposed beneath said outfeed roller of said dryer module to cool said outfeed roller. 
     
     
       44. The machine of claim 1, wherein said dryer module is double walled with insulation material inside the double walls, said dryer module including an inner wall subjected to heat generated by said pair of air knives and said pair of infrared heaters and an outer wall that is substantially cooler than said inner wall to protect workers near said dryer module. 
     
     
       45. The machine of claim 44, further comprising a first vent formed in an outer wall of said double walled dryer module near an upper end thereof and a second vent formed in said outer wall near a lower end thereof, whereby air circulates between said inner and outer walls of said double-walled dryer module by entering said lower vent and exiting said upper vent as a result of convection. 
     
     
       46. The machine of claim 1, further comprising a control means under control of a machine operator for determining said predetermined speed of said drive rollers.